Er掺杂强韧化Al2O3/TiAl复合材料

Reinforcing and toughening of Al_2O_3/TiAl composites by doping Er

以Ti、Al、TiO2为起始原料,以Er2O3为掺杂剂,原位热压合成了Er掺杂Al2O3/TiAl复合材料。通过XRD、SEM分析及力学性能测试,研究了不同Er2O3引入量对合成Al2O3/TiAl复合材料微观结构和力学性能的影响。结果表明:复合材料主要由TiAl、Ti3 Al、Al2 O3相和少量Al10 Er6 O24相组成,含Er相主要分布在基体相晶界处;掺杂0.01 mol Er2 O3制得的复合材料,经1250℃保温2 h真空热压烧结后表观断裂韧性达到最大值(10.41 MPa.m1/2),经1300℃保温2 h真空热压烧结后弯曲强度达到最大值(456.06 MPa);当Er2O3掺杂量增加到0.02 mol时,复合材料的弯曲强度和表观断裂韧性均呈减小趋势。微观结构分析表明,掺杂0.01 mol Er2O3的复合材料断口毛糙,颗粒尺寸变小,增强相分布较均匀,表明适量的Er2O3掺杂可细化复合材料晶粒尺寸,提高增强颗粒分布均匀度,起到增强增韧的效果。

Al2O3/TiAl composites doped with Er were successfully prepared from the powder mixture of Ti,Al,TiO2 and Er2O3 by hot pressing reaction synthesis technique.The phase compositions,room-temperature hardness and apparent fracture toughness of the composites were studied.The results show that the phases of the composites consist of TiAl,Ti3Al,Al2O3 and a small amount of Al10Er6O24.The phase containing Er and Al2O3 particles are distributed at grain boundary of the matrix.Flexural strength of the composites with 0.01 mol Er2O3 addition synthesized at 1300 ℃ for 2 h reaches the maximum value of 456.06 MPa,and apparent fracture toughness of the composites with 0.01 mol Er2O3 addition synthesized at 1250 ℃for 2 h reaches the maximum value of 10.41 MPa·m1/2,respectively.The flexural strength and apparent fracture toughness decrease with increasing of Er2O3 addition.The finer microstructure of the sample with addition of 0.01 mol Er2O3 is obtained and the reinforcing phase is distributed uniformly.Compared with the composites with 0.01 mol Er2O3 addition,the fracture morphology of Er free composites is more even.It is suggested that the properties and microstructure of the Al2O3/TiAl composites can be improved by doping Er with 0.01 mol Er2O3 addition.